10 pengantar jaringan komputer dan kom dat

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  • 1. PENGANTAR TEKNOLOGI INFORMASIPENGANTAR JARINGAN KOMPUTER DAN KOMUNIKASI DATA

2. Telecommunications SystemsOverviewData Communication : High speed data exchange between computers and/or other electronic devices via cable or wireless. (BussinesDictionary.com)Telecommunications can be defined as communication of data and information by electronic means such as telephone, radio, television, and computer, usually over some distanceComputer communications : a process in which one computer transfers data, information and instructions to another computerTelecommunications system is a collection of compatible hardware and software arranged to communicate data, information and instructions from one location to anotherTelecommunications systems can transmit text, graphic images, voice, and video information through communications channel 3. OverviewTelecommunications Systems(cont.)Contoh sistem telekomunikasi 4. OverviewTelecommunications Systems(cont.)Model telekomunikasi 5. Telecommunications Systems(cont.)Overview The telecommunications model consists of the following: A sending device that initiates an instruction to transmit data, information, or instructions. It can be a computer system, a terminal, a cellular telephone, a WebTV, a GPS receiver, an Internet-enabled PDA, or another device that originates the message. A communications device that connects the communications channel to a sending device. A communications channel or transmission media on which the data, instructions, or information travel. A communications device that connects the communications channel to a receiving device. A receiving device that accepts the transmission of data, information, or instructions. A communications software that controls and manages the activities and functions of the communications network. 6. 1. Communications DevicesTelecommunications System Components Devices that handle the movement of data in a computer network include: modemRouterHubNetwork interface cardsMultiplexerFront-end processorHost computer 7. 1. Communications DevicesTelecommunications System Components(cont.) MODEM (Modulation/Demodulation) Connects a communications channel to a sending or receiving device Computers process data as digital signals. Data, instructions, and information travel along a communication channel in either analog or digital form Modem converts analog to digital signals and digital to analog signals Converting signal from digital to analog is called modulation converting signal from analog to digital is called demodulation 8. 1. Communications DevicesTelecommunications System Components(cont.) 1. Dial-up modem usually is in the form of an adapter card that you insert in an expansion slot on a computer's motherboard One end of a standard telephone cord attaches to a port on the modem card and the other end plugs into a telephone outlet 2. Cable modem a digital modem that sends and receives digital data over the cable television (CATV) network A cable modem usually is an external device, in which one end of a cable connects to a CATV wall outlet and the other end plugs in a port in the system unit 9. 1. Communications DevicesTelecommunications System Components(cont.) 3. wireless modem allows access to the Internet wirelessly from a notebook computer, a PDA, a smart phone, or other mobile device Wireless modems, which have an external or built-in antenna, typically use the same waves used by cellular telephones 10. 1. Communications DevicesTelecommunications System Components(cont.) DEVICES CONNECTING NETWORKS 1. bridge Network bridging provides an easy way to connect 2 or more network to become a single big network without using router in order to share file, printer or Internet connection. Please note that all computers in different network that needs to be bridged must sit in same logical IP network. 11. 1. Communications DevicesTelecommunications System Components(cont.) 2. gateway a communications processor that connects networks that use different protocols by providing the translation from one set of protocols to another 3. router an intelligent bridge for large networks connect multiple networks and routs communications traffic to the appropriate network using the fastest available path many routers are protected by a built-in firewall 12. 1. Communications DevicesTelecommunications System Components(cont.) 4. front-end processor a small computer dedicated to communications management and is attached to the main, or host, computer in a large computer system The front-end processor is largely responsible for collecting and processing input and output to and from terminals and grouping characters into complete messages for submission to the CPU of the host computer 5. network card/network interface card (NIC) is an adapter card, that enables the computer or device that does not have built-in networking capability to access a network 13. 1. Communications DevicesTelecommunications System Components(cont.) 6. repeater a device that accepts a signal from a transmission medium, amplifies it, and retransmits it over the medium As a signal travels over a long distance, the signal undergoes a reduction in strength, an occurrence called attenuation 7. hub or switch a device that provides a central point for cables in a network receives data from many directions and then forwards it to one or more destinations 14. 2. Communications ChannelsTelecommunications System Components(cont.) Communications Channels communications path between two devices. composed of one or more transmission media The amount of signals that can travel over a communications channel sometimes is called the Bandwidth Baseband transmission media can transmit only one signal at a time broadband media can transmit multiple signals simultaneously 15. 2. Communications ChannelsTelecommunications System Components(cont.) Transmission media are one of two types: physical or wireless Physical transmission media use wire, cable, and other tangible materials to send communications signal Wireless transmission media send communications signals through the air or space using radio, microwave, and infrared signals Physical transmission media used in communications include twisted-pair cable, coaxial cable, and fiber-optic cable These cables typically are used within building or underground between buildings 16. 2. Communications ChannelsTelecommunications System Components(cont.) Physical Transmission Media 1. twisted-pair wire cable consists of one or more twisted-pair wires bundled together The wires are twisted together to reduce noise, which is an electrical disturbance that can degrade communications shielded twisted-pair (STP) cable, has a metal wrapper around each twisted-pair wire, which further reduces noise Cables that do not have this shielding are called unshielded twistedpair (UTP) 17. 2. Communications ChannelsTelecommunications System Components(cont.) 2. coaxial cable consists of a single copper wire surrounded by at least three layers: an insulating material, a woven or braided metal, and a plastic outer coating 3. fiber-optic cable consists of dozens or hundreds of thin strands of glass or plastic that use light to transmit signals Each strand, called an optical fiber advantage include (1) capability of carrying significantly more signals; (2) faster data transmission; (3) less susceptible to noise from other devices; (4) better security for signals during transmission; and (5) smaller size 18. 2. Communications ChannelsTelecommunications System Components(cont.)The speeds of various physical communications media when they are used in LANs 19. 2. Communications ChannelsTelecommunications System Components(cont.) Wireless Transmission Media Wireless transmission media used in communications include broadcast radio, cellular radio, microwaves, communications satellites, and infrared 1. Broadcast radio a wireless transmission medium that distributes radio signals through the air over long distances Bluetooth, Wi-Fi, UWB, and WiMAX communications technologies use broadcast radio signals 20. 2. Communications ChannelsTelecommunications System Components(cont.) 2. Celular radio a form of broadcast radio that is used widely for mobile communications, specifically wireless modems and cell phones Several categories of cellular transmissions exist, defining the development of cellular networks: 1G (first generation) transmitted analog data 2G (second generation) transmit digital data at speeds from 9.6 kbps to 19.2 kbps 3G (third generation) transmit digital data at speeds from 114 kbps to 2.4 Mbps 4G (fourth generation) transmit digital data at speeds up to 15 Mbps 3G technology allows users quickly to display multimedia and graphics, browse the Web, watch television or a video, have a video conference, and transfer data on a cellular device 21. 2. Communications ChannelsTelecommunications System Components(cont.) 22. 2. Communications ChannelsTelecommunications System Components(cont.) 3. microwafe high-frequency radio waves that are sent through the atmosphere and space Microwaves provide a high-speed signal transmission, and can transmit data at rates up to 4,500 times faster than a dialup modem Microwaves are limited to line-of-sight transmission, which means that microwaves must be transmitted in a straight line with no obstructions between microwave antennas To avoid possible obstructions, such as buildings or mountains, microwave stations often sit on the tops of buildings, towers, or mountains Microwave signals can carry thousands of channels at the same time. 23. 2. Communications ChannelsTelecommunications System Components(cont.) 4. communications satellite basically a microwave station placed in outer space The satellite receives the signal from the earth, amplifies the relatively weak